Letter Pid

Programmable Logic Controller (PLC) A type of industrial computer used to control machines and processes. The PLC accepts inputs from switches and sensors
and uses these inputs together with other data and program
logic to control output devices.

Proportional-Integral-Derivative (PID) Control A closed-loop control technique that seeks to minimize error by
reacting to three values, one that is proportional to the error,
one that is representative of the error over time, and one that is
representative of the rate of change of the error.



Proximity Sensor

A type of sensing switch that detects the presence or absence
of an object without physical contact.

Pulse Width Modulation (PWM) As applied to variable frequency drives, this is a technique for
controlling the voltage applied to an AC motor by varying the
pulse width while also controlling the frequency of the pulses.

Pushbutton
A control device used to manually open and close a set of
contacts.